The present invention relates to a fluid supply device which has vanes and vane grooves on an outer circumferential periphery of a rotary member.
It is proposed in JP-A 60-85288 that a fluid pump as a fluid supply device has an impeller on which vane grooves having different groove widths are provided on its outer circumferential periphery. More specifically, a set of vane grooves of different groove widths are arranged in a predetermined pattern on a part (fixed pitch) of the outer periphery of the impeller, and the set of vane grooves are arranged in repetition over the entire outer periphery of the impeller. This arrangement reduces peak of sound pressure generated at high frequencies corresponding to the product of the number of vanes and the rotational speed of the impeller.
However, because the set of vane grooves in the predetermined pattern appears repeatedly or regularly in one rotation of the impeller, a low frequency noise sound is generated each time the impeller rotates by the fixed pitch of pattern repetition. Thus, if this type of pump is used as an in-tank fuel pump for an internal combustion engine, the low frequency sound is likely to resonate with the fuel tank and generate a low frequency noise sound.